License	BSD3
Maintainer	tbidne@gmail.com
Safe Haskell	Safe
Language	Haskell2010

Common.Parsing.ParseErr

Description

Provides the ParseErr monoid.

Synopsis

data ParseErr
- = Err String
- | Help String

Documentation

data ParseErr Source #

ParseErr describes an error encountered while parsing. Errors are either a request for Help or some general error.

The algebra for ParseErr satisfies

  1. Identity: Err ""
  2. Help is an ideal: Help x <> Err y == Help x == Err y <> Help x
  3. Left-biased: l <> r == l, when it doesn't violate 1 or 2.

Strictly speaking property 2 is stronger than saying Help is an ideal. More precisely, the action by Err on Help in ParseErr is trivial.

Constructors

Err String
Help String

Instances

Instances details

Eq ParseErr Source #
Instance details Defined in Common.Parsing.ParseErr Methods (==) :: ParseErr -> ParseErr -> Bool # (/=) :: ParseErr -> ParseErr -> Bool #
Show ParseErr Source #
Instance details Defined in Common.Parsing.ParseErr Methods showsPrec :: Int -> ParseErr -> ShowS # show :: ParseErr -> String # showList :: [ParseErr] -> ShowS #
Semigroup ParseErr Source #
Instance details Defined in Common.Parsing.ParseErr Methods (<>) :: ParseErr -> ParseErr -> ParseErr # sconcat :: NonEmpty ParseErr -> ParseErr # stimes :: Integral b => b -> ParseErr -> ParseErr #
Monoid ParseErr Source #
Instance details Defined in Common.Parsing.ParseErr Methods mempty :: ParseErr # mappend :: ParseErr -> ParseErr -> ParseErr # mconcat :: [ParseErr] -> ParseErr #